Display Calibration

PerfectLum 3 medical display calibration software calibrates any computer display and projector to the international standard DICOM Part14 GSDF. PerfectLum 3 also adjusts the white level of the display, verifies calibration results and reports them in a history database.

PerfectLum 3 functions are listed below:

Calibration Section

Grayscale and color calibration

The calibration function allows you to calibrate your display according to the settings in preferences. Such calibration types as DICOM, Gamma, and CIE L* are possible with PerfectLum medical monitor calibration tool.

The medical monitor calibration software performs calibration on all shades of gray, achieving neutral gray shades and the lowest Delta E values. It also adjusts the white point to the desired target value in candelas, defined in preferences. This ensures that the observer sees colors correctly, as the aspect of an image is influenced by colors in the grays, not just luminance.

Automatic display adjustment

PerfectLum medical monitor calibration tool automatically adjusts display settings over the DDC/CI channel so that you don’t have to go into the OSD menu of the monitor. The display is automatically adjusted to a desired white level and optimum color temperature to ensure fast and easy calibration as well as high quality results.

Hardware calibration

Rather than saving on your computer’s graphics card, LUT (Look Up Table) calibration is saved inside any supported display. This secures the high precision of color temperature, gray shades, luminance and black point.

ICC profile generation

In the process of calibration a version 4 ICC profile with 3-dimensional color instruments and 16 bit precision is generated to save color characteristics for the given device. All colors in the created profile have low Delta E values. This profile allows cross-platform communication of color and ensures color-accurate viewing for all devices involved in image reproduction.

Start your calibration

First select the display you want to calibrate from the menu on the left, connect your measurement device, and then press the “Calibration” button – that’s all.

How To Match Two Displays For Identical Image Reproduction

Utilizing an application with two or more displays connected to one workstation side by side, or several displays connected to different workstations, you expect your images to look identical on every display.

For the images to look exactly the same on different displays, the displays are to reproduce them in an identical way. To achieve that, the following characteristics are to be the same on every display:

  • color temperature

  • white level

  • luminance response (often called Gamma)

To obtain the same color temperature on every display, one needs to correct it over the entire dynamic range of each display – from black to white. The adjustment of color temperature can be done either over the internal LUT of the display or over the graphics card LUT.

In addition to this, all displays are to have the same white level / maximum luminance. The white level is measured on DDL (Digital Driving Level) 255 in the center of the display. Luminance adjustment should be done over the brightness adjustment of the display.

The third factor that influences image reproduction is the luminance response of a display,  also known as Gamma. There exist different types of luminance response, such as DICOM, CIE L*, or Gamma. The luminance response value is to be the same on all displays. The adjustment is to be done over the internal LUT of the display or over the graphics card LUT.

Procedure:

  • Make sure all displays are set to the same values over the display OSD. Especially important are the color pre-settings, the brightness, and the contrast settings. Doing a factory reset on all displays can be helpful to make sure all of them start from a similar level.

  • Use only one measurement device. Measurement devices, unfortunately, still have considerable deviations when measuring color. So it is recommended to use the same device on all displays.

  • Identify the weakest display. If you want all displays to have the same white level, you need to know which of them has the lowest one and measure it. This white level will become the target value for all displays. It is important to have the same white level on displays that are connected to one workstation and installed side by side.

  • Set your target values for white level, color temperature and luminance response in PerfectLum Preferences.

  • Perform a display calibration with those same settings on each of your displays.

Read more about PerfectLum Quality Assurance for medical displays and Remote Display Management system.